The present invention relates to an actuator apparatus using a piezo or smart material and being adapted to operate at resonant frequencies. Methods of adjusting the resonant frequency of such an actuator and operating such an actuator at resonance are also disclosed.
Electrically-driven actuators are known in the art. When supplied with an alternating current, such actuators will react at a frequency that is a function of the frequency of the source current. According to the materials, mounting, and physical characteristics of their structures, such actuators will also have a frequency at which they begin to resonate when operated in such a fashion. Because operating in a resonant condition is typically seen as detrimental, in part due to the physical stress it imposes on the structure of the actuator, resonant frequencies are avoided, thereby imposing limitations on the allowable operating frequencies. The present invention addresses these shortcomings by providing an actuator apparatus that may be run effectively at resonant frequencies, a method of adjusting the resonant frequencies of such an actuator, and a method of maintaining operation of such an actuator in a resonant condition.
An actuator apparatus using a piezo or smart material and having mountable arms that enable customization of the apparatus for different applications is particularly suitable for resonant operation in part because of the fast reaction times of the piezo or smart material stack, and in part because of the ability to mount different arms allows for a degree of tuning of resonant frequencies, thereby enabling customization of the actuator for different applications.